1.) Field of the Invention
The invention herein relates to the field of folding knives and cutlery, more specifically to a foldable knife structure.
2.) Description of the Prior Art
Referring to FIG. 1, a conventional folding knife, such as the Taiwanese Patent xe2x80x9cImproved Type Folding Knifexe2x80x9d (application number 089210927), typically consists of a handle 1, a blade 2 pivotably conjoined to the front end of the said handle 1 and capable of being rotated into the said handle 1 and, furthermore, an internally disposed safety latch 16 and check block 18, the features of which include:
An actuating mechanism consisting of a locating block 10, a guide wheel 12, and a spring 14 is installed inside the handle 1; the locating block 10 is situated in the handle 1 away from the pivotable conjoinment area of the blade 2, the said guide wheel 12 is movably positioned on the blade 2 adjacent to the pivotable conjoinment area between the blade 2 and the handle 1, and the spring 14 has one extremity in the said locating block 10 and its opposite extremity extends between the pivotable conjoinment area of the blade 2 and of the handle 1 and finally against the said guide wheel 12.
Based on the preceding elaboration and referencing FIG. 1, in the said Taiwanese Patent, the said spring 14 must extend pass the pivotable conjoinment area between the blade 2 and the handle 1; during the rotating process of the said blade 2, the said spring 14 must be maintained in the said state against the guide wheel 12 such that as the said blade 2 is rotated into the said handle 1, the said guide wheel 12 moves from point A along the said check block 18 and when the said guide wheel 12 passes point B of the said check block 18, the elasticity of the said spring 14 impels the said guide wheel 12 along the said check block 18 down to point C of the said check block 18 and, furthermore, rests against the said guide wheel 12, causing the said blade 2 to be fully rotated into the said handle 1; as to rotate the said blade 2 out of the said handle 1, the said guide wheel 12 moves from point C along the said check block 18 such that when the said guide wheel 12 passes point B of the said check block 18, the elasticity of the said spring 14 impels the said guide wheel 12 along the said check block 18 up to point A of the said check block 18, causing the said blade 2 to be fully rotated out of the said handle 1.
Another variation of a conventional folding knife is represented by the U.S. patent xe2x80x9cOpening and Closing Assising Mechanism for Folding Knifexe2x80x9d (U.S. Pat. No. 6,145,202). Referring to FIG. 2, it consists of a handle 3, a blade 4 pivotably conjoined to the front end of the said handle 3 and capable of being rotated into the said handle 3, an arcuate limiting slot 30 adjacent to the pivotable conjoinment position between the said handle 3 and blade 4 having a curved orientation identical to the rotational orientation of the said blade 4, a slide slot 32 situated in the rear end of the said handle 3 away from the pivotable conjoinment position of the said blade 4, and a spring 34, with one extremity of the spring 34 movable inserted into the said slide slot 32 and its other extremity inserted through the said limiting slot 30 as well as fixed into a hole in the said blade 4.
Based on the preceding elaboration and referencing FIG. 2, in the said U.S. patent, the said spring 34 has one extremity capable of moving in the said slide slot 32 and an another extremity secured onto the said blade 4 such that as the blade 4 is rotated into the said handle 3, the said spring 34 flexes and its opposite extremity moves from point A along the said limiting slot 30 such that when the said spring 34 passes point B of the said limiting slot 30, the elasticity of the said spring 34 causes the said spring 34 to converge at one end of the said slide slot 32 and move away from the pivotable conjoinment position of the said blade 4 and handle 3 inside the said slide slot 32, thereby completing the full rotation of the said blade 4 into the handle 3, with the full rotation of the said blade 4 out of the said handle 3 achieved by reversing the said procedure.
However, in each of the said two conventional folding knives, since the blade, the handle, and the spring must be assembled together and, therefore, match each other, the fabrication of such matched components involve a troublesome and complex production process; for example, the fabrication of the said blade includes matching the spring to the limiting slot and the slide slot.
Additionally, in terms of production-line assembly, the assembly procedures of the said folding knives are too complicated; for example, the opposing extremities of the said spring have to be inserted through the said limiting slot 30 and fixed to the said hole, while the said guide wheel must be installed onto the said blade.
Furthermore, in terms of utilization, the leverage length of the said spring is excessively long such that the said blade is difficult to be folded into the said handle or rotated out of the said handle automatically.
In view of the numerous fabrication, assembly, and utilization inconveniences and difficulties of the conventional folding knives and the need to improve their shortcomings, the inventor of the invention herein conducted long-term research and experimentation that culminated in the successful research, development, and design of the foldable knife structure of the invention herein that comprises of a handle; a blade pivotably conjoined to a position adjacent to one end of the said handle; a set block adjacent to the pivotable conjoinment position of the said blade and handle, with the said set block having a detent notch; a spring situated at the other end of the said handle, with the opposite extremity of the said spring extending to a position on the said set block. When the said blade is folded into the said handle, the said spring is against the circumferential edge of the said set block, causing the said set block to produce torsion that rotates the said blade into a receiving slot. When the said blade is extended from the said receiving slot, the said spring impels the said set block to produce torsion that rotates the said blade out of the said receiving slot, causing the said blade to automatically bound out of the said receiving slot.
The objective of the invention herein is to provide a foldable knife structure, wherein when the said spring is not in a flexured state, the center portion of the said spring is against one side of the said receiving slot inside the said handle and when the said blade is folded inside the said receiving slot, the leverage length of the said spring is shorter such that a greater functional force and tension is exerted by the spring against the said set block which are utilized to firmly maintain the said blade in a folded state within the said receiving slot or to enable the rapid extension of the said blade from the receiving slot.